It’s always difficult to guarantee the software you’re using is secure but it is even harder still if the developer of the software or some malicious unknown third party has sneakily embedded a back way. I have outlined the 5 nastiest and most discreet backdoors found on the inter-webs yet. This list will leave you wondering whether there is anything dangerous lurking in your software and who can actually control it.

1# Back Orifice

It is nowhere near being the first backdoor although Back Orifice made audiences more aware of backdoors. It was generated in 1998 by the fine people of Cult of the Dead Cow hacker collective. This software allowed computers running Microsoft Windows to be operated remotely across a network.

Back Orifice was created to demonstrate the deeply-seeded security issues in Microsoft Windows 98. With this in mind, it offered features such as it being able to hide itself from the user which actually spawned a generation of black hat hackers who maliciously used this technique as a payload.

2# Sercom

It’s disastrous alone when your hardware product contains a backdoor but to claim you’ll fix it with the intention of just covering it up is just shameful. Unfortunately, that is exactly what happened towards the end of 2013 when numerous DSL gateways that utilised hardware produced by Sercom all of which held host to a manufacturer added backdoor on port 32764.

It wasn’t until April 2014 that a patch was released to solve the issue. Sadly, the “fix” that was offered only concealed access to that particular port. It wasn’t until a specially crafted packet (a “port knock”) was sent to expose it. At this point, there remains no real fix.

3# WordPress

Despite the fact that this platform is a popular, commercial success and carries plenty of powerful management systems, it is severely lacking from the security point of view. Just a few of the sneakiest breaches have come through via pirated versions of commercial “premium” plug-ins subtly patched to include backdoors. At least one of these patched plug-ins was so effectively obfuscated that even experienced WordPress users could have struggled to detect it.

If there wasn’t a good enough reason to avoid pirated software in the past, there is now.

4# Joomla

It’s not only WordPress that has experienced backdoor issues with plug-ins. Another CMS called Joomla has had their installations affected in a similar way. In one instance, the code for a free plug-in had been modified.

These kinds of attacks are generally performed as a method for getting back into a website that has been hacked as there aren’t many that would think twice about whether a CMS plug-in was the point of entry for an attack.

5# ProFTPD

This software is a widely used open source FTP server and was close to having a backdoor embedded in it. In 2010, hackers were able to gain access to the source code hosting server and implemented code which made it possible for the attacker to spawn a root shell by submitting the command “HELP ACIDBITCHEZ.”

Funnily enough the attackers took advantage of the zero-day exploit within ProFTPD itself to breach the site and embed the malicious code.